Foothold

ABSTRACT

There is provided a foothold comprising a tread, side portions positioned at both sides of the tread, legs to be inserted into a concrete wall, said tread, side portions and legs being formed of a core and first and second synthetic resins for covering the core, said second synthetic resins for covering the core of the legs having a substantially circular shape in cross section, and the first and second synthetic resins being integrated with each other, a plurality of fins provided axially on outer peripheries of the synthetic resins in a plurality of stages in the direction from the legs toward the side portions, and contact support pieces protruded from boundaries between the side portions and legs so as to bring into contact with the concrete wall. The contact support pieces can be reliably fitted to the wall surface to reliably prevent the foothold from hanging down, and the plurality of fins provided on the legs are reliably and easily fitted to the holed defined in the wall surface to reliably fix the foothold to the manhole wall, thereby providing the foothold capable of enduring for a long period of use.

BACKGROUND THE INVENTION

1. Field of the Invention

The present invention relates to a foothold comprising a tread, sideportions positioned at both sides of the tread and legs to be insertedinto a concrete wall.

2. Prior Art

As a conventional foothold comprising a tread, side portions positionedat both sides of the tread and legs to be inserted into a concrete wall,there is known a foothold, for example, as disclosed in Japanese UtilityModel Laid-Open Publication 6-71899 having the construction thatfall-out prevention members are provided at portions close to the tipends of the legs and the tip ends of the legs are pointed while collarsare provided at the portions close to the centers of the legs.

In the conventional foothold, there is a possibility of producing a gapbetween holes defined in a concrete wall into which legs of a footholdare inserted and fall-out prevention members provided at portions closeto the legs owing to the long period of use of the foothold, causing adrawback that the foothold is rattled vertically and laterally in theholes and it lacks in stability. Further, although the conventionalfoothold includes collars at boundaries between side portions and legsto bring into contact with the concrete wall, these collars can notsufficiently support the tread of the foothold, which causes a problemthat the foothold hangs down when a load is applied to the tread.

SUMMARY OF THE INVENTION

The present invention has been made in view of the problem of the priorart. It is an object of the present invention to provide a footholdcapable of reliably and easily fitting the legs of the foothold to theholes defined in the manhole and so forth so that the foothold can bereliably fixed to the manhole wall and so forth and it can endure for along period of use.

To achieve the above object, the foothold according to the first aspectof the present invention is characterized in comprising a tread 2, sideportions 3 positioned at both sides of the tread 2, legs 4 to beinserted into a concrete wall, said tread 2, side portions 3 and legs 4being formed of a core 5 and first and second synthetic resins 6 and 6afor covering the core 5, said second synthetic resins 6a for coveringthe core 5 of the legs 4 having a substantially circular shape in crosssection, and the first and second synthetic resins 6 and 6a beingintegrated with each other, a plurality of fins 8 provided axially onouter peripheries of the synthetic resins 6a in a plurality of stages inthe direction from the legs 4 toward the side portions 3, and contactsupport pieces 9 protruded from boundaries between the side portions 3and legs 4 so as to bring into contact with the concrete wall.

The foothold according to the second aspect of the present invention ischaracterized in that the upper surface of the tread 2 is inclinedupward from the central portion toward the both ends thereof at theangle of 1 to 5 degrees.

The foothold according to the third aspect of the present invention ischaracterized in that reflectors are provided on the tread 2 at portionsadjacent both ends thereof, wherein the light reflector is red and theother reflector is green.

The foothold according to the fourth aspect of the present invention ischaracterized in that the tread 2 has a wave-shaped grip portionprovided at the inner side surface thereof in the axial direction andanother wave-shaped grip portion provided at the lower surface of thetread 2 in the axial direction and having irregularities thereon.

The foothold according to the fifth aspect of the present invention ischaracterized in further comprising belt-shaped projections 22 formedalong the outer ends of both side portions 3.

The foothold according to the sixth aspect of the present invention ischaracterized in further comprising rise portions 24 directed upwardfrom both ends of the tread 2, said rise portion having side portionsprovided on upper ends of the rise portions 24.

The foothold according to the seventh aspect of the present invention ischaracterized in further comprising blow receiving portions 26 at thefront side of the tread 2 when the legs 4 are embedded into the concretewall.

The foothold according to the eighth aspect of the present invention ischaracterized in comprising a tread 2, side portions 3 positioned atboth sides of the tread 2, legs 4 to be inserted into a concrete wall,said tread 2, side portions 3 and legs 4 being formed of a core 5, firstand second synthetic resins 6 and 6a for covering the core 5, saidsecond synthetic resins 6a for covering the core 5 of the legs 4 havinga substantially circular shape in cross section, and the first andsecond synthetic resins 6 and 6a being integrated with each other, aplurality of fins 8 provided axially on outer peripheries of thesynthetic resins 6a in a plurality of stages in the direction from thelegs 4 toward the side portions 3, characterized in that the uppersurface of the tread 2 is inclined upward from the central portiontoward the both ends thereof at the angle of 1 to 5 degrees, andreflectors are provided on the tread 2 at portions adjacent both endsthereof, wherein the right reflector is red and the left reflector isgreen, while the tread 2 has a wave-shaped grip portion provided at theinner side surface thereof in the axial direction and anotherwave-shaped grip portion provided at the lower surface of the tread 2 inthe axial direction and having irregularities thereon, and also hasbelt-shaped projections 22 formed along the outer ends of both sideportions 3 and blow receiving portions 26 provided at the front side ofthe tread 2 when the legs 4 are embedded into the concrete wall, andcontact support pieces 9 protruded from boundaries between the sideportions 3 and legs 4 so as to bring into contact with the concretewall.

The foothold according to the ninth aspect of the present invention ischaracterized in comprising a tread 2, side portions 3 positioned atboth sides of the tread 2, legs 4 to be inserted into a concrete wall,said tread 2, side portions 3 and legs 4 being formed of a core 5, firstand second synthetic resins 6 and 6a for covering the core 5, saidsecond synthetic resins 6a for covering the core 5 of the legs 4 havinga substantially circular shape in cross section, and the first andsecond synthetic resins 6 and 6a being integrated with each other, aplurality of fins 8 provided axially on outer peripheries of thesynthetic resins 6a in a plurality of stages in the direction from thelegs 4 toward the side portions 3, characterized in that rise portions24 directed upward from both ends of the tread 2 and having sideportions on upper ends thereof are formed, the upper surface of thetread 2 is inclined upward from the central portion toward the both endsthereof at the angle of 1 to 5 degrees, and reflectors are provided onthe tread 2 at portions adjacent both ends thereof, wherein the rightreflector is red and the left reflector is green, while the tread 2 hasa wave-shaped grip portion provided at the inner side surface thereof inthe axial direction and another wave-shaped grip portion provided at thelower surface of the tread 2 in the axial direction and havingirregularities thereon, and also has blow receiving portions 26 providedat the front side of the tread 2 or at the front side of rise portionwhen the legs 4 are embedded into the concrete wall, and contact supportpieces 9 protruded from boundaries between the side portions 3 and legs4 so as to bring into contact with the concrete wall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a foothold according to a first embodiment ofthe present invention;

FIG. 2 is a front view of the foothold in FIG. 1;

FIG. 3 is a side view of the foothold in FIG. 1;

FIG. 4 is an enlarged sectional view of the foothold taken along lineA--A in FIG. 1;

FIG. 5 is an enlarged sectional view of the foothold taken along lineB--B in FIG. 1;

FIG. 6 is a plan view of a main portion of a foothold which is fixed toa manhole inner wall and so forth;

FIG. 7 is a plan view of a foothold according to a second embodiment ofthe present invention;

FIG. 8 is a front view of the foothold in FIG. 7; and

FIG. 9 is a side view of the foothold in FIG. 7.

PREFERRED EMBODIMENT OF THE INVENTION

First Embodiment (FIGS. 1 to 6)

A foothold according to a first embodiment of the invention is describedwith reference to FIGS. 1 to 6, wherein FIG. 1 is a plan view of afoothold, FIG. 2 is a front view thereof, FIG. 3 is a side view thereof,FIG. 4 is an enlarged sectional view of the foothold taken along lineA--A in FIG. 1, FIG. 5 is an enlarged sectional view of the footholdtaken along line B--B in FIG. 1, and FIG. 6 is a plan view of a mainportion of a foothold which is fixed to a manhole inner wall and soforth.

In FIG. 1, a reference numeral 1 depicts an entire configuration of afoothold. The foothold 1 comprises a tread 2, side portions 3 positionedat both sides of the tread 2, and legs 4 fixed to a concrete wall and soforth. These tread 2, side portions 3 and legs 4 are formed of a core 5made of iron and having substantially U-shape as viewed from the planeand first synthetic resins 6 such a polypropylene cover the core 5 forkeeping the core 5 from rusting. Slip prevention patterns 7 are formedon the entire surfaces of the tread 2 and side portions 3.

Second synthetic resins 6a covering the core 5 of the legs 4 has asubstantially circular shape in cross section and a plurality of (e.g.,two) fins 8 are provided axially on the outer peripheries of the secondsynthetic resins 6a in a plurality of (e.g., three) stages in thedirection from the legs 4 side toward the side portions 3, wherein thefins 8 are integrated with the second synthetic resins 6a. Tip ends ofthe fins 8 are slightly curved so as to expand its diameter outward.

Denoted by 9 are contact support pieces protruded from boundariesbetween the side portions 3 and the legs 4 so as to bring into contactwith the concrete wall surface.

In the foothold 1 having the construction set forth above, the legs 4are inserted into holes 14 defined in an inner wall 11 of a manhole in astate where the tip ends of the fins 8 are pressed by inner hole walls14 of holes 11 after filling epoxy resins 12 and so forth in the holes11 of the inner wall 10, while the contact support pieces 9 protrudedfrom the boundaries between the side portions 3 and the legs 4 arebrought into contact with the manhole wall surface 13. Subsequently, theentire foothold 1 is slightly pulled toward a person. As a result, thetip ends of the fins 8 are retained relative to the inner hole walls 14of the holes 11 while they are expanded in diameter so that the lateralrattling of the legs 4 can be reliably prevented while interlocked withthe epoxy resins 12 and so forth. Further, the contact support pieces 9are brought into contact with the manhole wall surface 13 to support thefoothold 1 so that the foothold 1 is more reliably prevented fromhanging down. With these operations, the legs 4 are air tightly broughtinto contact with the inner wall 10, and hence the legs 4 can bereliably fixed to the inner wall 10 (see FIG. 6).

The upper surface of the tread 2 is varied in the manner that it isinclined upward from the center S toward both ends thereof at the angleof 1 to 5 degrees. As a result, both feet of a person can be placed onthe tread 2 with safety so that the working can be safely performed bythe person.

Reflectors 15 are provided on both end corners of the tread 2. If theright reflector 15 is red while the left reflector 18 is green, theright and left positions of the foothold are made clear, therebyorienting the foothold in a specific direction.

A wave-shaped grip portion 16 is provided on the tread 2 at the innerside thereof in the axial direction thereof. Another wave-shaped gripportion 18 having irregularities 17 is formed on the tread 2 at thelower surface thereof.

In this case, although it is normally conceived that the person goes upand down the foothold 1 while gripping the foothold 1 that is positionedseveral stages above the foothold 1 on which the person places his orher both legs, the tread 2 can be easily gripped because the wave shapeis formed on the inner side of the tread 2 in the axial direction. Stillfurther, since the tread 2 has the wave-shaped grip portion 18 havingthe irregularities 17 on the lower surface of the tread 2 in the axialdirection, both hands can be prevented from slipping so that the personcan go up and down the foothold 1 with safety.

Denoted by 19 are belt-shaped projections formed along the outer endportions of the side portions 3. With the provision of these projections19, even if both legs are placed on the side portions 3 when working,the working can be performed by the person with safety while both legsare not slipped laterally from the tread 2 owing to the projections 19.

It is possible to cover the back surfaces of the projections 19 byreflectors 20, as shown by imaginary lines in FIGS. 2 and 3, whereby theareas of the reflectors increase so that the position of the foothold 1is made clearer.

Second Embodiment (FIGS. 7 to 9)

A foothold according to a second embodiment of the invention isdescribed with reference to FIGS. 7 to 9. FIG. 7 is a plan view of thefoothold, FIG. 8 is a front view thereof and FIG. 9 is a side viewthereof.

In these figures, rise portions 21 are formed on both ends of the tread2 while the former is directed upward from the latter. Side portions 3are formed on the upper ends of the respective rise portions 21.Reflectors 22 are provided on portions adjacent both ends of the tread 2and the portion adjacent the rise portions 21 of the side portions 3.Since other components of the foothold 1 of the second embodiment aresubstantially the same as those of the first embodiment, they aredenoted by the same reference numerals, and hence the explanationthereof is omitted.

In the foothold 1 having the construction set forth above, even if bothlegs are placed on both ends of the tread 2 when using the foothold 1,both legs are prevented from laterally slipping by the rise portions 21,thereby providing a safe foothold.

At least one blow receiving portion 23 that is used when embedding thefoothold 1 formed of synthetic resins in the concrete wall is providedon the front sides of the rise portions 21, and the blow receivingportion 23 is integrally formed with the first synthetic resins 6 of thetread 2 at the rise portions 21.

There is a case where the legs 4 are hardly embedded or inserted intothe inner wall of a concrete wall even if the foothold 1 is pressedagainst the inner wall by hands when fixing the foothold 1 to theconcrete wall. In this case, it is normally conceivable that the frontside of the tread 2 is blown by a hammer and so forth to embed or insertthe legs 4 in the inner wall. With the provision of the blow receivingportions 23, the front side of the tread 2 is hardly damaged, and hencethe foothold 1 can be reliably fixed to the concrete wall. Further, asshown by an imaginary line of FIG. 8, two blow receiving portions 23 maybe formed on the front side of the tread 2 or one blow receiving portion23 may be formed on the central front side of the tread 2 if the widthof the tread is narrow.

According to the foothold of the first aspect of the invention, sincethe foothold comprises a tread, side portions positioned at both sidesof the tread, legs to be inserted into a concrete wall, said tread, sideportions and legs being formed of a core and first and second syntheticresins for covering the core, said second synthetic resins 6a forcovering the core of the legs having a substantially circular shape incross section, and the first and second synthetic resins beingintegrated with each other, a plurality of fins provided axially onouter peripheries of the synthetic resins in a plurality of stages inthe direction from the legs toward the side portions, and contactsupport pieces protruded from boundaries between the side portions andlegs so as to bring into contact with the concrete wall, the contactsupport pieces can be reliably fitted to the wall surface to reliablyprevent the foothold from hanging down, and the plurality of finsprovided on the legs are reliably and easily fitted to the holed definedin the wall surface to reliably fix the foothold to the manhole wall,thereby providing the foothold capable of enduring for a long period ofuse.

According to the foothold of the second aspect of the invention, sincethe upper surface of the tread is inclined upward from the centralportion toward the both ends thereof at the angle of 1 to degrees, bothlegs of a person can be placed on the upper surface of the tread withsafety, and hence the person can reliably perform working.

According to the foothold of the third aspect of the invention, sincereflectors are provided on both cornered portions of the tread whereinthe right reflector is red and the other reflector is green, thepositions of the right and left portions of the foothold are made clear,thereby providing a safe foothold capable of orienting the foothold inspecific direction.

According to the foothold of the fourth aspect of the invention, sincethe tread has a wave-shaped grip portion provided at the inner sidesurface thereof in the axial direction and another wave-shaped gripportion provided at the lower surface of the tread in the axialdirection having irregularities thereon, a person can easily grip thetread when going up and down the tread, and both hands are preventedfrom slipping from the tread, thereby providing a safe foothold.

According to the foothold of the fifth aspect of the invention, sincethe foothold comprises belt-shaped projections formed along the outerends of both side portions, both legs are not laterally slipped from thetread owing to the projections, thereby providing a safe footholdcapable of working with safety.

According to the foothold of the sixth aspect of the invention, sincethe foothold comprises rise portions directed upward from both ends ofthe tread, and the rise portions have side portions provided on upperends of the rise portions, even if both legs are placed on both ends ofthe tread when using the foothold, both legs are not laterally slippedfrom the tread owing to the rise portions, thereby providing a safefoothold.

According to the foothold of the seventh aspect of the invention, sincethe foothold comprises blow receiving portions at the front side of thetread when the legs are embedded in the concrete wall, the foothold ishardly damaged, when it is fixed to the concrete wall, thereby providinga foothold capable of being reliably fixed to the concrete wall.

According to the foothold of the eighth and ninth aspects of theinvention, since the foothold comprises all the components as set forthin the first to seventh aspects of the invention, the contact supportpieces can be reliably fitted to the wall surface to reliably preventthe foothold from hanging down, and the plurality of fins provided onthe legs are reliably and easily fitted to the holes defined in the wallsurface to reliably fix the foothold to the manhole wall. Further, bothlegs are not laterally slipped from the tread owing to the projectionsor rise portions even if both legs are placed on side portions whenusing the foothold, thereby assuring the reliable working by the person.Still further, the foothold is oriented in the specific direction andthe tread can be easily gripped by hands of the person when going up anddown the tread, and the foothold is hardly damaged. More still further,the foothold can be reliably fixed to the wall surface, and it canendure for a long period of use.

What is claimed is:
 1. A foothold comprising an elongate,foot-supporting tread, side portions positioned at both ends of thetread and extending rearwardly transverse to the tread, each said sideportion having a leg cantilevered therefrom, said legs being adapted tobe inserted into a wall, said tread, side portions and legs being formedof a rigid core covered by first and second synthetic resin, said secondsynthetic resin covering the core of the legs and having a substantiallycircular shape in cross section, and the first and second syntheticresins being integrated with each other, a plurality of fins provided onouter peripheries of the synthetic resins in a plurality ofaxially-spaced stages in the axial direction from the legs toward theside portions, an upper surface of the tread being inclined upward froma central portion toward both ends thereof at an angle of 1 to 5degrees, reflectors provided on the tread at portions adjacent both endsthereof, wherein a first said reflector on one end of the tread is onecolor and a second said reflector on the other end of the tread isanother color, the tread having a wave-shaped grip portion provided atan inner, rearward side surface of the tread between said side portionsand extending in the axial direction of said tread, another wave-shapedgrip portion provided at the lower surface of the tread and extending inthe axial direction of said tread, said another wave-shaped grip portionhaving irregularities thereon, belt-shaped projections formed along theouter sides of both side portions for assisting in preventing a footfrom sliding off an end of said tread, blow receiving portions providedat a front side of the tread when the legs are embedded in the wall soas to be disposed in an inserted position, said blow receiving portionsbeing adapted to receive blows that will drive said legs into a wall,and contact support pieces projecting from boundaries between the sideportions and legs and contacting the wall in the inserted position.
 2. Afoothold according to claim 1, wherein said first reflector has anL-shape and defines a corner transitioning said tread into therespective said side portion, said first reflector reflects light fromportions of upper and lower surfaces of said tread and side portion, aportion of the front surface of said tread, and a portion of an outerside surface of said side portion.
 3. A foothold according to claim 1,wherein said first reflector includes a first reflector member disposedon said tread adjacent said one end thereof which reflects light fromupper, front, and lower surfaces of said tread, and a second reflectormember disposed on said side portion adjacent said one end of said treadwhich reflects light from the upper, outer side, and lower surfaces ofsaid side portion.
 4. A foothold according to claim 1, wherein said onecolor is green and said another color is red, so that all footholdsmounted in a manhole have the same orientation with said red reflectorsvertically aligned with one another.
 5. A foothold comprising anelongate, foot-supporting tread, side portions cantilevered fromrespective ends of the tread, a pair of legs cantilevered from therespective said side portions, said legs being adapted to be insertedinto a wall, said tread, side portions and legs being formed of a corecovered with first and second synthetic resins, said second syntheticresin covering the core of the legs and having a substantially circularshape in cross section, and the first and second synthetic resins beingintegrated with each other, a plurality of fins provided on outerperipheries of the synthetic resins in a plurality of axially spacedstages in the axial direction from the legs toward the side portions,raised portions directed upward from both ends of the tread andextending upwardly from the upper surface of said side portions, theupper surface of the tread being inclined upward from a central portionthereof toward the both ends thereof at an angle of 1 to 5 degrees,reflectors provided on the tread at portions adjacent both ends thereof,a right said reflector is one color and a left said reflector is anothercolor, a wave-shaped grip portion provided at an inner side surface ofthe tread in the axial direction of tread between said side portions,another wave-shaped grip portion provided at a lower surface of thetread in the axial direction of tread and having irregularities thereon,blow receiving portions provided on one of a front side of the treadwhich face away from the legs and a front side of said raised portionwhen the legs are embedded in the wall so as to be in an insertedposition, and contact support pieces which protrude from boundariesbetween the side portions and legs and contact the wall in the insertedposition.
 6. A foothold according to claim 5, wherein said firstreflector has an L-shape and defines a corner transitioning said treadinto the respective said side portion, said first reflector reflectslight from portions of upper and lower surfaces of said tread and sideportion, a portion of the front surface of said tread, and a portion ofan outer side surface of said side portion.
 7. A foothold according toclaim 5, wherein said first reflector includes a first reflector memberdisposed on said tread adjacent said one end thereof which reflectslight from upper, front, and lower surfaces of said tread, and a secondreflector member disposed on said side portion adjacent said one end ofsaid tread which reflects light from upper, outer side, and lowersurfaces of said side portion.
 8. A foothold according to claim 5,wherein said one color is green and said another color is red, so thatall footholds mounted in a manhole have the same orientation with saidred reflectors vertically aligned with one another.